This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The goal of this research is to continue to develop a model of infection with Campylobacter jejuni, a bacterium that causes food and water-borne disease (mainly diarrhea). The objectives are to 1) determine if healthy subjects develop short-term (less than 6 month) protection to reinfection with C. jejuni;and 2) characterize the immune responses to C. jejuni infection. Information obtained will be used in development of a vaccine against Campylobacter infections. Volunteers will be screened for eligibility within 60 days prior to enrollment. Screening will include obtaining informed consent prior to any study procedure. This will be followed by medical history, physical examiniation, review of current medications, blood samples for safety labs (WBC, Hct, Hgb, platelet count;chemistry panel;screening for HIV, HLA-B27, HBV, and HCV);urine pregnancy testing for females. Stool will be tested for infection. Eligible volunteers will be enrolled in the study and admitted to the GCRC on Day -1. They will drink a measured dose of C. jejuni on Day 0, and followed for appoximately 9 inpatient days, during which time we expect at least 75% to develop a diarrheal illness, which will be promptly treated with replacement fluids (oral or IV, as indicated) and antibiotics. During the inpatient period, subjects will be assessed for any adverse events, and blood and stool specimens will be analyzed for markers of infection and markers of immune response. Subjects must have resolved or resolving symptoms and two negative stool cultures greater than 12 hours apart to be eligible for discharge, and will be seen in outpatient follow-up at 21, 28, 35, 60 and 90 days for additional AE assessments and blood and stool analysis. Eight subjects will return for redosing approximately 98 days after the initial dose, with the same inpatient and outpatient follow-up as above. Few or none should develop a diarrheal illness. Four naive (previously unexposed) subjects will also receive the dose on Day 98 to confirm a 75% illness rate with this dose. They will be followed as the initial group was. All participants will be assessed by phone 6 months after the final dose they received.